RHINOPTERA MARGINATA. 445 



Rhode Island; it was twenty-two inches in width and fourteen in length from 

 snout to ends of ventrals. 



Back and tail brown; lower surfaces white, brownish toward outer angles 

 of pectorals. 



Rhinoptera lalandii. 



Plate 48, fig. 5-6 (teeth). 



Rhinoptera lalandii Muller & Henle, 1841, Plagios., p. 182; Dumeril, 1865, Elasm., p. 648; Gunth., 



1870, Cat. fishes Brit, mua., 8, p. 494; Ribeiro, 1907, Arch. Mus. nac, 14, p. 193. 

 Mylorhina lalandii Gill, 1865, Ann. N. Y. lye, 8, p. 136. 



Width of disk about twice its length, little less than the length of the tail. 

 Head wider than long, moderately notched in front of the fontanel and between 

 the rostral fins. Anterior narial valves confluent in a broad flap reaching the 

 mouth, straight and fringed on the edge, free and wider backward with angles 

 nearly acute. Teeth in seven rows, in cases five in the upper jaw: — a median 

 row of teeth three to six times as wide as long, a lateral row at each side of it in 

 which the width is from two to three times the length, and an outer two rows in 

 which width and length are about equal. Pectorals with length and width 

 nearly equal, outer angle acute, narrowly rounded at the tip. Ventrals more 

 than half as broad as long, convex on the end. Dorsal subtriangular, margins 

 nearly straight; upper angle rounded, posterior little produced; origin opposite 

 ends of ventral bases; tip not as far back as tips of ventrals. Skin smooth. 

 Specimen at hand measures as follows: — width 20^, snout to vent IO2 and vent 

 to end of tail 23 inches. 



Back brown; beneath white, brownish on outer portions of pectorals. 



Off eastern coasts of South America. 



Rhinoptera marginata. 

 Plate 48, fig. 4 (teeth). 



Myliobatis marginnla Geoffroy Saint-Hilaire, 1827, Descript. Egypt, 1, p. 334, pi. 25, f. 3, 4. 

 Rhinoptera marginata Cuv., 1829, Reg. anim., 2, p. 401: Voigt, 1S32, Thierreich, 2, p. 525; Muller & 



Henle, 1841, Plagios., p. 181; Dumeril, 1865, Elasm., p. 645; Gunth., 1870, Cat. fishes Brit, mus., 



8, p. 493. 

 Myliobatis (Rhinoptera) marginata Owen, 1845, Gdont., p. 46, pi. 25, f. 2, 3. 



Disk about twice as broad as long; anterior margin convex, nearly straight, 

 posterior concave. Pectoral slightly falciform; outer angle blunted, hinder 

 sharp. Teeth in nine rows; median row nearly three times as wide as long, 



